Visual Basic Wie lese ich eine CSV-Datei und zeige die Werte in einem Datagrid an?

Question

Ich benutze VB 2005, wie öffne ich eine CSV-Datei und lese die Spalten/Zeilen und zeige die Werte in einem Datagrid an?

CSV-Datei Beispiel: jsmith, jsmith @ hotmail.com

Ich möchte dann eine Aktion auf jede Zeile heißt jeden Benutzer ausführen, wie würde ich das tun?

Ich bin ein Neuling, wie Sie sagen können, aber glücklich zu lernen.

Dank

Answer 1

Verbrauch:

Dim reader As New Common.CSVReader("C:\MyFile.txt") 
reader.DisplayResults(dgvMyView) 

Klasse:

Imports System.Windows.Forms 
Imports System.IO 
Imports System.Text.RegularExpressions 

Public Class CSVReader 
    Private Const ESCAPE_SPLIT_REGEX = "({1}[^{1}]*{1})*(?<Separator>{0})({1}[^{1}]*{1})*" 
    Private FieldNames As String() 
    Private Records As List(Of String()) 
    Private ReadIndex As Integer 

    Public Sub New(File As String) 
     Records = New List(Of String()) 
     Dim Record As String() 
     Dim Reader As New StreamReader(File) 
     Dim Index As Integer = 0 
     Dim BlankRecord As Boolean = True 

     FieldNames = GetEscapedSVs(Reader.ReadLine()) 
     While Not Reader.EndOfStream 
      Record = GetEscapedSVs(Reader.ReadLine()) 
      BlankRecord = True 
      For Index = 0 to Record.Length - 1 
       If Record(Index) <> "" Then BlankRecord = False 
      Next 
      If Not BlankRecord Then Records.Add(Record) 
     End While 
     ReadIndex = -1 
     Reader.Close() 
    End Sub 

    Private Function GetEscapedSVs(Data As String, Optional Separator As String = ",", Optional Escape As String = """") As String() 
     Dim Result As String()  
     Dim Index As Integer 
     Dim PriorMatchIndex As Integer = 0 
     Dim Matches As MatchCollection = _ 
      Regex.Matches(Data, String.Format(ESCAPE_SPLIT_REGEX, Separator, Escape)) 

     ReDim Result(Matches.Count) 

     For Index = 0 to Result.Length - 2 
      Result(Index) = Data.Substring(PriorMatchIndex, Matches.Item(Index).Groups("Separator").Index - PriorMatchIndex) 
      PriorMatchIndex = Matches.Item(Index).Groups("Separator").Index + Separator.Length 
     Next 
     Result(Result.Length - 1) = Data.Substring(PriorMatchIndex) 

     For Index = 0 To Result.Length - 1 
      If Regex.IsMatch(Result(Index), String.Format("^{0}[^{0}].*[^{0}]{0}$", Escape)) Then _ 
    Result(Index) = Result(Index).Substring(1, Result(Index).Length - 2) 
      Result(Index) = Replace(Result(Index), Escape & Escape, Escape) 
      If Result(Index) Is Nothing Then Result(Index) = "" 
     Next 

     GetEscapedSVs = Result 
    End Function 

    Public ReadOnly Property FieldCount As Integer 
     Get 
      Return FieldNames.Length 
     End Get 
    End Property 

    Public Function GetString(Index As Integer) As String 
     Return Records(ReadIndex)(Index) 
    End Function 

    Public Function GetName(Index As Integer) As String 
     Return FieldNames(Index) 
    End Function 

    Public Function Read() As Boolean 
     ReadIndex = ReadIndex + 1 
     Return ReadIndex < Records.Count 
    End Function 


    Public Sub DisplayResults(DataView As DataGridView) 
     Dim col As DataGridViewColumn 
     Dim row As DataGridViewRow 
     Dim cell As DataGridViewCell 
     Dim header As DataGridViewColumnHeaderCell 
     Dim Index As Integer 
     ReadIndex = -1 

     DataView.Rows.Clear() 
     DataView.Columns.Clear() 

     For Index = 0 to FieldCount - 1 
      col = new DataGridViewColumn() 
      col.CellTemplate = new DataGridViewTextBoxCell() 
      header = new DataGridViewColumnHeaderCell() 
      header.Value = GetName(Index) 
      col.HeaderCell = header 
      DataView.Columns.Add(col) 
     Next 

     Do While Read() 
      row = new DataGridViewRow() 
      For Index = 0 to FieldCount - 1 
       cell = new DataGridViewTextBoxCell() 
       cell.Value = GetString(Index).ToString() 
       row.Cells.Add(cell) 
      Next 
      DataView.Rows.Add(row) 
     Loop 
    End Sub 
End Class 

Answer 2

Hier ist eine einfache Lösung ist, die ODBC ADO.Net Text-Treiber verwendet:

Dim csvFileFolder As String = "C:\YourFileFolder" 
Dim csvFileName As String = "YourFile.csv" 

'Note that the folder is specified in the connection string, 
'not the file. That's specified in the SELECT query, later. 
Dim connString As String = "Driver={Microsoft Text Driver (*.txt; *.csv)};Dbq=" _ 
    & csvFileFolder & ";Extended Properties=""Text;HDR=No;FMT=Delimited""" 

Dim conn As New Odbc.OdbcConnection(connString) 

'Open a data adapter, specifying the file name to load 
Dim da As New Odbc.OdbcDataAdapter("SELECT * FROM [" & csvFileName & "]", conn) 
'Then fill a data table, which can be bound to a grid 
Dim dt As New DataTable 
da.Fill(dt) 

grdCSVData.DataSource = dt 

Einmal gefüllt, Sie können Eigenschaften bewerten der Datentabelle wie ColumnName, um alle Potenzen der ADO.Net-Datenobjekte zu nutzen.

In VS2008 können Sie Linq verwenden, um den gleichen Effekt zu erzielen.

Answer 3

Verwenden Sie die TextFieldParser das ist built into VB.NET. Google hat mich gefunden this example

Using MyReader As New Microsoft.VisualBasic.FileIO.TextFieldParser _ 
    ("C:\test\info.csv") 

    'Specify that reading from a comma-delimited file' 
    MyReader.TextFieldType = FileIO.FieldType.Delimited 
    MyReader.SetDelimiters(",") 

    Dim currentRow As String() 
    While Not MyReader.EndOfData 
    Try 
     currentRow = MyReader.ReadFields() 
     With Me.dgvReport.Rows 
     .Add(currentRow) 'Add new row to data grid view' 
    End With 
    Catch ex As Microsoft.VisualBasic.FileIO.MalformedLineException 
    MsgBox("Line " & ex.Message & _ 
     "is not valid and will be skipped.") 
    End Try 
End While 
End Using 

Answer 4

Bibliothek Verwenden Sie das Lesen für Sie zu tun.

CsvHelper (eine Bibliothek, die ich pflege) ist über NuGet verfügbar.

Ich bin nicht vertraut mit VB, also wenn jemand dies in VB ändern möchte, bitte tun. Obwohl es nur ein paar Zeilen Code sind.

var streamReader = // Create StreamReader to CSV file. 
var csvReader = new CsvReader(streamReader); 
var myObjects = csvReader.GetRecords<MyObject>(); 
// You can then databind the myObjects collection to a datagrid. 
// If you don't want the whole file, you can read row by row. 
var myObject = csvReader.GetRecord<MyObject>();